The present invention generally relates to the dispensing of filtered, bottled water. More specifically, the invention relates to a shutoff device that monitors the number of bottles used and then disables further use of the filter when the filter has reached the end of its useful life. The device can also provide an early warning signal to the user that the filter is nearing the end of its useful life.
Self-contained filters for removing unwanted minerals and chemicals such as chlorine have become increasingly popular with bottled water users. These filters may be threadably attached or otherwise connected to the opening of a bottled water container, or may be contained within the water dispenser unit. Various devices are also known for monitoring water flow and then interrupting water flow after a predetermined use.
Some prior art devices have provided techniques for opening a pressure vessel containing a carbon filter used in water purification. However, such techniques are cumbersome and undesirable for the user. Thus, it is desirable to provide an economical self-contained dispenser shutoff and filter cartridge which may be easily replaced when a monitor indicates that the filter has reached the end of its useful life.
In general, prior art patents and known water dispensing disabling devices (herein termed xe2x80x9cshutoff devicesxe2x80x9d) with a filter have tended to concentrate on ways of interrupting water flow through the bottle opening once the filter has reached the end of its useful life, by physically blocking water flow. However, this may result in an interruption in dispensing when the water container still has a substantial volume of water in it, which is not desirable from a user viewpoint. To overcome this problem, some prior art devices provide specific shutoff mechanisms so that when the filter cartridge is removed, dispensing is stopped; these devices also require a separate filter monitor device to visually or audibly warn the user that the filter has reached the end of its useful life. Many such shutoff devices have also tended to have a number of moving parts, increasing the risk of part malfunction.
However, there is a need for a water filter shutoff device which monitors water usage and automatically disables dispensing when the filter has reached the end of its useful life, without the need to rely on visual or audible warning signals. Such a filter shutoff device would also preferably meet the following constraints. Given space constraints, the shutoff device preferably is integral with the filter, and should not unduly impede flow through the filter. The shutoff device would also preferably allow presetting at the time of manufacture to change the allowable water flow or application uses, so that the device could be used with differently rated filters and differently sized water containers. The device should be economical to manufacture and preferably not require an entirely new mold or any substantial additional investment in assembly equipment or fixtures, while also being relatively simple in design with few moving parts to reduce quality control risks. The shutoff device would also preferably disable dispensing, without interrupting water flow from the currently used water container, when a monitor indicates the useful life of the filter is over.
A filter shutoff device preferably meets NSF criteria, including qualifying as a filter xe2x80x9cperformance indication devicexe2x80x9d (PID) under NSF standards, and include component materials that have existing NSF approval for extraction. If no filter monitor/PID is provided for a water dispenser with a filter, obtaining NSF approval currently requires that the filter be tested to work at 200% of its rated capacity. If a PID is provided, the filter need only be tested to work at 120% of its rated capacity for NSF approval. For example, if a filter is rated for 150 gallons, and a filter PID is provided, the filter need only have a capacity of 180 gallons, as opposed to 300 gallons if no filter PID is provided. This is a significant added cost feature for a filter manufacturer, since providing a filter capable of filtering 300 gallons requires additional media content resulting in a significant added cost.
Filter shutoff devices must also be provided with venting in some manner to allow continuous water flow, without xe2x80x9clock upxe2x80x9d. One problem with such devices is that, upon initial use, as water from the inverted water bottle flows into the device, water pressure/water hammer conditions may cause unfiltered water to leak or spurt out of the venting channels and into the dispensing unit. A sufficient volume of water may escape filtration in this manner, such that the device may not receive NSF approval for, e.g., lead testing. It is also desirable to provide a filter shutoff device which overcomes this problem.
Accordingly, an object of the present invention is to provide a shutoff device integral with a filter and useable with a water dispenser, in which the water dispenser is automatically disabled at the end of the useful life of the filter.
Another object of the invention is to provide a filter shutoff device which does not impede or interrupt water flow between the water dispensing device and a water source such as an inverted water bottle. A further object is to provide such a device that qualifies as filter PID under NSF standards, enabling the more economical manufacture of the filter.
Yet another object is to provide a filter shutoff device which may be manufactured in an economical manner, such that the device monitors the number of water containers used, disables further dispensing after a predetermined number of uses, and then may be discarded and replaced with a new device.
A further object is to provide a filter shutoff device which automatically disables the connection between the device and a water container, rather than simply providing a visual indication of end of filter life, and rather than maintaining the ability to make this connection and physically impeding or interrupting water flow.
A still further object is to provide such a device with an appropriate size and configuration, together with appropriately located and sized vent holes, to ensure that unfiltered water does not leak out of the device and be dispensed.
The following terms are used in the claims of the patent as filed and are intended to have their broadest meaning consistent with the requirements of law. Where alternative meanings are possible, the broadest meaning is intended. All words used in the claims are intended to be used in the normal, customary usage of grammar and the English language.
xe2x80x9cAutomatic filter shutoff devicexe2x80x9d means a device in fluid communication with a water container which filters water and then interferes with the ability to dispense water from the container after a predetermined amount of water usage (i.e., the xe2x80x9cshutoffxe2x80x9d feature), which may generally correspond to the useable life of the filter, has been reached. xe2x80x9cAutomaticxe2x80x9d in this context means that shutoff occurs without the need for user intervention, such as without the need for the user to respond to a visual or audible signal from a filter monitor.
xe2x80x9cMonitoring and disabling mechanismxe2x80x9d means a mechanism which monitors filter life by monitoring water usage, and which includes a shutoff feature.
The objects mentioned above, as well as other objects, are solved by the present invention, which overcomes disadvantages of prior filter shutoff devices for water dispensers, while providing new advantages not believed associated with such devices.
In one preferred embodiment, An automatic filter shutoff device is provided, and is removably connected to a water container and in fluid communication with a water dispenser. The device is adapted to monitor water dispensing and disable dispensing after a predetermined amount of water usage. The device includes a housing containing a water filter and removably connected to the water container; and a monitoring and disabling mechanism having a shutoff apparatus moveable between first and second locations, the first location being one in which water dispensing is monitored by the mechanism, and the second location being one in which the mechanism is placed in an interfering position with the connection between the housing and the water container. The shutoff apparatus automatically moves into the second location after the predetermined amount of water usage has occurred, and without interrupting water dispensing from the then-connected water container, so that the used filter shutoff device must be replaced in order to reestablish connection to a successive water container. Preferably, the predetermined amount of water usage generally corresponds to the useable life of the filter.
In a preferred embodiment, the filter shutoff device is adjustable so that dispensing may be disabled after differing amounts of water usage. In one preferred embodiment, the shutoff apparatus includes a plunger whose vertical height may be varied, and the second location is one in which the plunger obstructs the connection of the filter housing and the water container. The monitoring and disabling mechanism may include a filter cap with a downwardly depending leg having a locking window engageable with a locking tab located on the shutoff apparatus. The engaging surfaces of the locking tab and locking window may be angled to facilitate entry of the tab within the window, and to prevent disengagement of the tab and window.
In a particularly preferred embodiment, the plunger has a top surface with a throat opening and annular side walls with spaced openings, and wherein the surface area of the orifice is approximately equal to the surface area of the side openings.
The monitoring and disabling mechanism may include a filter cap mounting radially disposed, opposing teeth, and the shutoff apparatus may include a rotary indexer having a radially protruding tab iteratively communicating with the teeth. In this embodiment, the rotary indexer monitors water dispensing by tracking the number of water containers used during dispensing Preferably, the monitoring and disabling mechanism is a NSF-compliant performance indication device.
A visual indicator, such as a color band located on an outer surface of the filtering and disabling mechanism, may be provided to warn the user that the filter is nearing the end of its useful life. The monitoring and disabling mechanism may also include a visual indication to facilitate adjusting of the mechanism for differing water usages.
In an alternative embodiment, the monitoring and disabling mechanism may include a helical-shaped spring, and a rotary index engageable with teeth having a number corresponding to the predetermined amount of water usage.
In another aspect of the invention, a filter mechanism is provided which is connected to a bottled water container and adapted to be inverted and placed in fluid communication with a water dispenser. The filter mechanism includes a housing containing a water filter with a throat removably connected to the bottled water container. The throat is a restricted orifice sized, such as less than one inch or about xc2xe-inches in diameter, for example, to permit a volumetric flow rate of not greater than about 7,500 ml./min. of water passage during inversion of the water container and initial flow from the container into the filter. A plurality of vent holes located in an upper surface of the filter housing are provided; the vent holes are sized to permit air from the filter to escape into the water container and allow continuous water flow from the container into the filter. When a new water container is connected to the housing, the water level within the filter does not reach the vent holes in the filter housing. This embodiment may, but need not, including a monitoring and disabling mechanism having a shutoff apparatus as described above.